In an amplifier, there may be a non-dominant frequency pole whose frequency value is proportional to gm/C, where gm is the transconductance of the output stage and C is the total capacitance at the output node (for example, C may include the capacitance of the load at the output node, the capacitance of the output node itself, and parasitic capacitances).
For high speed applications, the non-dominant pole may need to be pushed out to high frequencies. A low non-dominant pole frequency can lead to bad phase margin (under-damped behavior) and low bandwidth. To increase the frequency of the non-dominant pole, the amplifier may be designed with increased current in the output stage of the amplifier to increase the gm of the output stage. This, however, may lead to increasing power consumption. Additionally, as gm/C may be inherently limited by manufacturing process, increasing current may not be sufficient to increase the frequency of the non-dominant pole of the output stage.
Accordingly, there is a need for an amplifier with increased or improved non-dominant pole frequencies with improved bandwidth and settling time, without increasing the current of the output stage.